IP and Domain Reputation Checker
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Your email has bounced back from the recipient

If you are viewing this page, you have likely sent an email that was not delivered to the recipient. In the resulting bounced email message, you have found and clicked this link: https://www.spamhaus.org/returnc/vol/

The problem doesn’t relate to your email set-up.

Why has my email not been delivered?

  • The problem is with the recipient’s email server configuration.
  • This is not due to an issue with your email set-up.
  • It is not because you are listed on one of our blocklists.

What do I need to do next?

If the email is urgent or essential:

  • Call the recipient and tell them that they have an issue with receiving emails.
  • Ask the recipient to urgently contact their email server administrator. This page provides the information required to correct this issue: Using our public mirrors? Check your return codes now.

For non-urgent emails

  • Try and resend the email in 24 hours, allowing the recipient’s email administrators time to resolve the problem.

Want more technical detail?

We’ve provided the above information for the everyday email user; however, if you’re technically minded and want to learn more, keep reading…

There is a fair usage policy for our free Public Mirrors. When we observe excessive use of our Public Mirrors, we will stop usage. This is to protect the infrastructure for whom it is intended, i.e., small- scale, non-commercial users.

Where users have had access revoked but continue to query the Public Mirrors, we have introduced an error code. This provides a clear signal that there is an issue, indicating that our DNSBLs aren't protecting their email stream. Mail server configurations need to be updated to accommodate these error codes.

How to configure MTAs to parse error codes

If error codes aren't correctly parsed when using the Public Mirrors, all email messages may be treated as "LISTED" or "NOT_LISTED." To avoid this, see our instructions on how to use the Public Mirrors with popular MTAs.

How to continue using Spamhaus DNSBLs

If you exceed the Public Mirrors' fair policy usage, you can sign up for the commercial Data Query Service. The good news is that this service comes with additional benefits:

  1. Real time updates – this is a commercial grade service
  2. Access to an increased number of blocklists, including:
    • Zero Reputation Domain Blocklist (ZRD)
    • Hash Blocklists (HBL)
    • Authentication Blocklist (Auth BL)

You can get immediate access to the DQS via a free 30-day trial. The sign-up process is simple, and the service only takes minutes to configure. Full DQS configuration details can be found on our technical documents site.